The specific aims of this research are (1) To refine methodology for identifying cases of resident-to-resident elder mistreatment (RREM) in long-term care facilities using triangulation methodology that derives information from resident, staff, and incident reports;(2) To conduct the first systematic prevalence study of RREM in a representative sample of 10 long-term care facilities;and (3) To describe the victims and perpetrators of RREM with respect to clinical, functional, and other characteristics and the environmental and situational contexts in which RREM episodes occur. For the purpose of this study, we define RREM as negative and aggressive physical, sexual, or verbal interactions between long-term care residents, that in a community setting would likely be construed as unwelcome and have high potential to cause physical or psychological distress. We hypothesize that RREM is prevalent and associated with a variety of subject, environmental, and facility characteristics, such as gender, time of day, and residence on a dementia unit. After final testing of an instrument that was developed by marrying the best methodologies from "interpersonal aggression" and "nursing home behavioral disturbance research" (Specific Aim 1), a prevalence study in a representative sample of facilities will be conducted and an adjusted facility and study-wide RREM prevalence estimated (Specific Aim 2). Finally, the characteristics of RREM subjects, perpetrators, and events will be examined both qualitatively and quantitatively (Specific Aim 3). Enhancements in this revision include (1) improvement and clarification of the case finding methodology, (2) clearer articulation of the analytic strategy which is linked to specific hypotheses, and (3) substantially improved safeguards for participating facilities, some of which have already been recruited (see letters of support from the facilities and the New York State Department of Health). Additional pilot studies demonstrate high resident participation rates, widespread staff familiarity with RREM, and the feasibility of a novel method adapted for staff identification of RREM in real time (the "shift coupon" technique). Strengths of this work include its prospective case finding methodology, a more modest but representative sample that reduces operational complexity, and the integration of qualitative and quantitative methods for event description. The project also weds a diverse research group uniquely qualified to conduct this work, including Mark Lachs (a geriatrician who studies elder abuse), Jeanne Teresi (a statistician, psychometrician and gerontologist with decades of experience in long-term care research), and Karl Pillemer (a sociologist with renowned expertise in nursing home organization and elder abuse). The Long Term Goals of this research are to garner information about RREM that will serve as the basis for interventions that could prevent it, or avert undesirable associated outcomes when it is unavoidable. PUBLIC HEALTH RELEVANCE: This study will examine the frequency and nature of resident to resident elder mistreatment (RREM) in long term care, such as physical and verbal aggressive behavior that occurs between residents. While the problem of staff abuse of residents in long term care has received extensive attention, the problem of resident to resident mistreatment is unstudied. Using residents and staff as reporters, this research will determine how frequently the problem occurs, what the episodes are like, and which residents are most likely to be involved. It is hoped that the research will lead to interventions that can minimize the occurrence of RREM.